1. Field of the Invention
This invention relates to improvements in set screws and more particularly, but not by way of limitation, to a set screw adapted to require minimum torque in use.
2. Description of the Prior Art
Pipe sections are frequently secured in end-to-end or in tandem relation by means of coupling members of a push-on pipe bell or fitting bell elements which do not require the use of threaded connection between the fitting of the end of the pipe section or pipe joint. It is common practice to utilize set screws cooperating between the bell fitting and the pipe end inserted thereto to restrain the pipe against movement due to the internal pressure within the pipe. Many of the pipe sections and fittings used in such installations is ductile iron pipe having the inner periphery thereof coated with cement. The set screw normally extends radially through the side wall of the bell fitting and into engagement with the outer periphery of the pipe. When a set screw is torqued to a high value in order to penetrate the outer periphery of the pipe for providing a secure connection therewith, the cement coating is frequently cracked, and the cement may loosen from the wall of the pipe or fitting and fall out. Of course, when the cement is thus lost from the inner wall of the pipe or fitting, the iron material from which the pipe or fitting is constructed is exposed to the water, or other fluid, moving through the pipe. This has long been a problem in the industry.